package zuoye;

class Animal {
 public Animal() {
  System.out.println("父类无参构造");
 }

 void sound() { System.out.println("zuoye.Animal sound"); }
}
class Dog extends Animal {
 public Dog() {
  System.out.println("子类无参构造");
 }
 @Override
 void sound() { super.sound();
  System.out.println("11"); }
 void sound(int volume) { System.out.println("Bark at volume " + volume); }
}
public class Main {
 public static void main(String[] args) {



 Animal a = new Dog();

 a.sound();




 }
}